Many computing devices have enclosures and coverings that include metallic surfaces that give the devices an aesthetically pleasing and durable look and feel. The metallic surfaces typically have a thin passivation layer that increases the corrosion resistance and wear resistance of the metal. This thin passivation layer is generally formed using an electrolytic process called anodizing, whereby the metal part acts as an anode. During anodizing, a portion of the exposed metal is converted to a metal oxide layer, sometimes referred to as an anodic film or layer. The anodic layer can be dyed to give the metal surfaces any of a number of different colors.
Often, the enclosures for computing devices include non-metallic portions. For example, touch pad covers and radio frequency antenna windows are required to be made of non-metallic materials in order to allow proper operation of underlying touch pads and radio frequency antennas, respectively. These non-metallic portions can be made of non-capacitive and/or radio frequency transparent materials such as plastic or glass. One design challenge associated with including non-metallic portions within metal enclosures is maintaining a sleek and consistent overall metallic-looking enclosure. The non-metallic portions can be dyed to match the color of adjacent dyed anodized metal surfaces. However, it can be difficult to get an exact color match between non-metallic portions and metallic portions. This is because the non-metallic portions and the anodic layers of the metallic portions generally accept different types of dyes. The result is the dyed non-metallic portions have a slightly different color than the dyed anodized metallic surfaces, which can detract from the consistent color and continuous look of the enclosures.